Children (6-12yrs) from low-income households are at an elevated risk for obesity, type 2 diabetes, and other associated comorbidities and cardiometabolic dysfunction. The vast majority of obesity prevention interventions targeting these children are delivered during the 9-month school-year, either in school or during afterschool programs. Substantial evidence developed over the past decade consistently indicates that all improvements in weight and other health outcomes achieved during the school year from in-school or afterschool programs are erased during summer vacation. Observational studies indicate that summer vacation exerts a negative effect on the obesogenic behaviors (i.e., activity, screen time, diet, sleep) and weight status of children, especially children from low-income households. Emerging evidence from observational studies shows that when children attend summer programs, they engage in higher levels of physical activity, consume more foods/beverages that meet federal guidelines for child nutrition/caloric density, and maintain a more consistent sleep schedule. Thus, evidence indicates that summer programs exert a beneficial influence on children?s obesogenic behaviors. Unfortunately, children from low-income households have limited access to summer programs. The proposed study builds upon the scientific literature that examines the effects of demand-side financing, such as financial incentives to improve adults? health behaviors and the use of vouchers/subsidies in low-income populations and developing countries, and applies this intervention approach to childhood obesity in low-income households. We hypothesize that by addressing the cost barrier to participating in summer programs, increased attendance at existing community-operated summer programs will occur, and this will lead to marked improvements in children?s obesogenic behaviors. In turn, we hypothesize improvements in obesogenic behaviors will result in a reduction in excessive, unhealthy weight gain over summer. For this study, we will rigorously test the impact of providing access to existing community-operated summer programs, through the use of a voucher program, on weight status (i.e., BMI z- score) and obesogenic behaviors of 1st-3rd grade children from low-income households. Using a randomized design, we will compare changes in weight status and obesogenic behaviors of 420 children from low-income households randomized to one of two conditions: voucher program for summer programming or comparison/control. We believe this study is significant because the research questions are of high policy relevance to federal, state, and local policymakers, with the majority of parents supporting the use of public funds to provide access to summer programs. We believe this study is innovative because it draws from the demand-side financing literature, which is widely used to change adult health behaviors, and will test a novel and innovative voucher program to eliminate cost barriers to attending existing community-operated summer programs as an intervention to overcome the health disadvantages of growing up in poverty.